Whiteflies

Whiteflies can definitely be a nuisance to your flowers, plants, and vegetables.

So, what are whiteflies?

Whiteflies are about 1/10 to 1/16 inch long and look like tiny moths. They are closely related to aphids, mealybugs, and scale, all of which feed by ‘sucking’ sap from your plants, flowers, and vegetables. They are found on the undersides of leaves and are active during the daytime when the temperature is warm. Some species of whiteflies can become serious pests to certain vegetable crops, greenhouse plants, or ornamental plants. These pests thrive in warmer climates, as well as indoors and in greenhouses,  and they can reproduce throughout the year with several overlapping generations.

What damage do they cause?

Whiteflies damage plants by ‘sucking’ out the juices (sap) from plants. Because large amounts of sap can be removed by whiteflies, heavily infested plants can be seriously weakened, making the plant grow poorly. The leaves of the infected plant can turn yellow, appear dry, and fall off or drop prematurely. In addition, whiteflies suck out more sap than they can digest, which makes the whiteflies excrete the excess as a sweet, sticky substance. This substance covers the leaf’s surface and can lead to a sooty mold.  Additionally, these secretions can attract an infestation of ants.  Both the loss of the plant’s sap and the presence of this mold can interfere with the plant’s photosynthesis process.

How can you ‘control’ whiteflies?

Plants in or around your house often become infested with whiteflies through the introduction of already infested plants. It’s important to inspect your plants regularly and remove older leaves that are heavily infested with whiteflies.

Whiteflies have many natural enemies in the garden setting, such as spiders, lady beetles, and lacewings. However, many people use insecticides to control these enemies which prevent these predators from effectively controlling the whitefly population.

A mechanical technique that can help you control whitefly infestation is to vacuum them with a small, hand held vacuum cleaner. Try to vacuum the adult whiteflies in the early morning when the temperature is cool and the whiteflies are slow moving. It’s a good idea to put the vacuum bag in your freezer for 24 hours to kill the whiteflies.

The best strategy for avoiding whiteflies is a pro-active approach of excluding plants that typically attract whiteflies from your landscape plans.  Hiring an experienced and certified landscape planner will go a long way in protecting your yard from infestation.